1. HKUST-Shenzhen Research Institute; No. 9 Yuexing 1st RD, Hi-Tech Park Nanshan Shenzhen 518057 P. R. China
2. Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction; Hong Kong University of Science and Technology; Clear Water Bay Hong Kong
3. State Key Laboratory for Mechanical Behavior of Materials; Xi'an Jiaotong University; Xi'an 710049 P. R. China
4. Department of Physics and Organic and Carbon Electronics Lab (ORaCEL); North Carolina State University; Raleigh NC 27695 USA
5. Institute of Polymer Optoelectronic Materials and Devices; State Key Laboratory of Luminescent Materials and Devices; South China University of Technology; Guangzhou 510640 P. R. China